Many conventional reclosable bags made of synthetic resin film include a fastener (referred to also as zipper). Such a fastener is provided in reclosable bags to prevent the ingress of dust and/or water as well as to prevent articles placed in a reclosable bag from being lost. Most conventional reclosable bags with a fastener are arranged to be unfastened and fastened by opening and closing the fastener by hand or provided with a slider for opening and closing the fastener. That is, in the case of using a slider, a fastener F is provided at a mouth E of a reclosable bag W and an opening/closing slider 10 is fitted to the fastener F, as shown in FIG. 30. Sliding the slider 10 fitted to the fastener F in the direction indicated by the arrow R causes the fastener F to be opened, while sliding in the direction indicated by the arrow S causes the fastener F to be closed.
As shown in FIG. 28(A), such a fastener F typically includes a male engageable member F1 having a projected streak portion F3 and a female engageable member F2 having a recessed engagement groove F4 into which the projected streak portion F3 is fitted engageably and disengageably, the members being provided in an adhesive manner, respectively, on one inner surface W1 and the other inner surface W2 at a mouth E of a bag. When the fastener F of the reclosable bag W is initially closed, the projected streak portion F3 of the male engageable member F1 is fitted in the engagement groove F4 of the female engageable member F2. The mouth E of the reclosable bag W can be opened by inserting the projection 10A of the slider 10 forcibly between the projected streak portion F3 and the engagement groove F4 of the fastener F, as shown in FIG. 28(B), and sliding (moving) the slider 10. The mouth E of the reclosable bag W can be closed by sliding (moving) the slider 10 with the narrowed portion 10C of the slider 10 being placed around the male engageable member F1 and the female engageable member F2, as shown in FIG. 28(C), so that the narrowed portion 10C presses the mouth E of the reclosable bag W on either side thereof.
FIGS. 29(A) and 29(B) are perspective views of the conventional slider 10, respectively, an overall view and view of the slider cut from center. In these figures, for descriptive convenience, the slider is turned upside down (the projection 10A and the narrowed portion 10C are directed upward) contrary to its normal use. As shown in these figures, the conventional slider 10 includes the projection 10A provided in a standing manner within an inner space 10E having a wide central portion nearer one side along its centerline, sidewalls 10D, 10D provided in a standing manner on lateral ends of a bottom portion 10B, and wall portions 10F, 10F constituting the narrowed portion 10C nearer the other side. The slider 10 may be fitted later to the fastener F provided at the mouth E of the reclosable bag W. This arrangement allows the slider 10 to be fitted, as described above, by forcing the projection 10A of the slider 10 downward and placing the narrowed portion 10C around the mouth E of the reclosable bag W. In this state, sliding the slider 10 in the direction indicated by the arrow R (see FIG. 30) allows the fastener F at the mouth E to be opened, while sliding in the direction indicated by the arrow S allows the fastener F at the mouth E to be closed.
Sliders of the type shown in FIG. 30 are most useful, but a little more complex die is necessarily required for manufacturing of such sliders. Hence, the present applicant has proposed such a sectional slider for fastener as shown in FIGS. 26 and 27. That is the slider 31 for fastener includes a slider member 32 formed with a projection 32A for disengaging a male engageable member F1 from a female engageable member F2 both included in a fastener F, the male engageable member F1 having a projected streak portion F3 and the female engageable member F2 having an engagement groove into which the projected streak portion F3 is fitted engageably and disengageably, the members being provided, respectively, on one inner surface and the other inner surface at a mouth of a bag, and another slider member 33 formed with a narrowed portion 33C for fitting the male engageable member F1 into the female engageable member F2. The slider 31 for fastener also has a structure in which the separately-formed slider members 32 and 33 are fitted to each other (refer to Patent Literature 1).
In addition, sidewalls 32C are formed on lateral ends of the slider member 32 having the projection 82A, while columnar portions 33A are formed on either side of the narrowed portion 33C in the slider member 33, and recessed portions 33E are formed on the outer side of the respective columnar portions 33A, whereby the sidewalls 32C can be fitted to the respective recessed portions 33E (refer to Patent Literature 1).
Patent Literature 1: Japanese Patent Application No. 2008-148231